1. Field of Invention
The present invention relates to a hydraulic torque impulse generator, and more particularly, to a low-friction, efficient, and durable hydraulic torque impulse generator.
2. Related Prior Art
A pneumatic power wrench is often equipped with a hydraulic torque impulse generator for transmitting power, such as torque for fastening or slacking nuts or screws. The efficiency of the hydraulic torque impulse generator is critical for the efficiency of the pneumatic power wrench.
A hydraulic torque impulse generator generally includes a cylinder, an axle inserted through the cylinder, blades non-rotational but movable relative to the axle, and springs for achieving the movement of the blades relative to the axle. To achieve high efficiency, suppress vibration, and reduce noise, the cylinder includes a chamber with a cross-sectional shape that looks like a circle overlapping another circle. Thus, the chamber includes a waist portion. Friction between each of the blades and the wall of the chamber reaches a maximum when the blade moves past the waist portion of the chamber. The maximum friction reduces the speed of rotation of the axle, thus reducing the power of the hydraulic torque impulse generator. Moreover, the maximum friction between the blades and the cylinder would wear out the blades or cylinder soon so that the blades or the cylinder would have to be replaced soon.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.